Canker sores are also known as aphthous ulcers. They are shallow, painful sores in the mouth that are usually red or may sometimes have a white coating over them. You might get them on the inside of your lips, the insides of your cheeks, the base of your gums or under your tongue. Canker sores are different from fever blisters, which usually are on the outside of your lips or the corners of your mouth. They usually pop up alone, but sometimes they show up in small clusters.
Your mouth might tingle or burn before the actual sore appears. Soon, a small red bump rises. Then after a day or so it bursts, leaving an open, shallow white or yellowish wound with a red border. The sores are often painful and can be up to an inch across, although most of them are much smaller. Occasionally, someone who gets canker sores may also develop a fever and feel sluggish and uncomfortable.
The good news is that canker sores are not contagious like some other mouth sores, such as cold sores. So you can’t spread canker sores by sharing food or kissing someone. Cold sores, however, are caused by the herpes simplex virus, which can pass from person to person. If you have a sore and you’re wondering if it’s of the cold or canker variety, just look at where it’s located. Cold sores usually appear outside the mouth, around the lips, chin, or nostrils. Canker sores, on the other hand, are always found inside the mouth.
Anyone can get canker sores, but women and people in their teens and 20s get them more often. Canker sores may run in families, but they aren’t contagious. Doctors don’t know what causes canker sores, but they may be triggered by citrus fruits, stress, fatigue, illness, physical trauma, hormonal changes, menstruation, sudden weight loss, food allergies, sodium lauryl sulfate (found in toothpaste), immune system reactions and deficiencies in vitamin B12, iron, and folic acid may contribute to their development. Nicorandil and certain types of chemotherapy are also linked to aphthous ulcers.
Vitamin B12 has been found to be effective in treating recurrent aphthous ulcers. It works regardless of whether there is a vitamin deficiency present. Suggestions to reduce the pain caused by an ulcer include: avoiding spicy food, rinsing with salt water or over-the-counter mouthwashes, proper oral hygiene and non-prescription local anesthetics. Antimicrobial mouthwashes may reduce the painfulness and duration of ulcers and increase the number of days between ulcerations, without reducing the number of new ulcers. Liquorice root extract may help heal or reduce the growth of aphthous ulcers if applied early on and is available in over-the-counter patches.